Materials Data on Ta2NiS5 by Materials Project
Ta2NiS5 crystallizes in the orthorhombic Cmcm space group. The structure is two-dimensional and consists of two Ta2NiS5 sheets oriented in the (0, 1, 0) direction. Ta4+ is bonded to six S2- atoms to form TaS6 octahedra that share a cornercorner with one TaS6 octahedra, edges with four equivalent TaS6 octahedra, and edges with two equivalent NiS4 tetrahedra. The corner-sharing octahedral tilt angles are 58°. There are a spread of Ta–S bond distances ranging from 2.44–2.57 Å. Ni2+ is bonded to four S2- atoms to form NiS4 tetrahedra that share corners with two equivalent NiS4 tetrahedra and edges with four equivalent TaS6 octahedra. There are two shorter (2.23 Å) and two longer (2.26 Å) Ni–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to two equivalent Ta4+ and two equivalent Ni2+ atoms. In the second S2- site, S2- is bonded in a distorted T-shaped geometry to three equivalent Ta4+ atoms. In the third S2- site, S2- is bonded in a distorted T-shaped geometry to two equivalent Ta4+ and one Ni2+ atom.